Originální popis anglicky:
accept - accept a new connection on a socket
Návod, kniha: POSIX Programmer's Manual
#include <sys/socket.h>
int accept(int
socket, struct sockaddr *restrict
address,
socklen_t *restrict
address_len );
The
accept() function shall extract the first connection on the queue of
pending connections, create a new socket with the same socket type protocol
and address family as the specified socket, and allocate a new file descriptor
for that socket.
The
accept() function takes the following arguments:
- socket
- Specifies a socket that was created with socket(),
has been bound to an address with bind(), and has issued a
successful call to listen().
- address
- Either a null pointer, or a pointer to a sockaddr
structure where the address of the connecting socket shall be
returned.
- address_len
- Points to a socklen_t structure which on input
specifies the length of the supplied sockaddr structure, and on
output specifies the length of the stored address.
If
address is not a null pointer, the address of the peer for the
accepted connection shall be stored in the
sockaddr structure pointed
to by
address, and the length of this address shall be stored in the
object pointed to by
address_len.
If the actual length of the address is greater than the length of the supplied
sockaddr structure, the stored address shall be truncated.
If the protocol permits connections by unbound clients, and the peer is not
bound, then the value stored in the object pointed to by
address is
unspecified.
If the listen queue is empty of connection requests and O_NONBLOCK is not set on
the file descriptor for the socket,
accept() shall block until a
connection is present. If the
listen() queue is empty of connection
requests and O_NONBLOCK is set on the file descriptor for the socket,
accept() shall fail and set
errno to [EAGAIN] or [EWOULDBLOCK].
The accepted socket cannot itself accept more connections. The original socket
remains open and can accept more connections.
Upon successful completion,
accept() shall return the non-negative file
descriptor of the accepted socket. Otherwise, -1 shall be returned and
errno set to indicate the error.
The
accept() function shall fail if:
- EAGAIN or EWOULDBLOCK
-
O_NONBLOCK is set for the socket file descriptor and no connections are
present to be accepted.
- EBADF
- The socket argument is not a valid file
descriptor.
- ECONNABORTED
-
A connection has been aborted.
- EINTR
- The accept() function was interrupted by a signal
that was caught before a valid connection arrived.
- EINVAL
- The socket is not accepting connections.
- EMFILE
- {OPEN_MAX} file descriptors are currently open in the
calling process.
- ENFILE
- The maximum number of file descriptors in the system are
already open.
- ENOTSOCK
- The socket argument does not refer to a socket.
- EOPNOTSUPP
- The socket type of the specified socket does not support
accepting connections.
The
accept() function may fail if:
- ENOBUFS
- No buffer space is available.
- ENOMEM
- There was insufficient memory available to complete the
operation.
- EPROTO
- A protocol error has occurred; for example, the STREAMS
protocol stack has not been initialized.
The following sections are informative.
None.
When a connection is available,
select() indicates that the file
descriptor for the socket is ready for reading.
None.
None.
bind() ,
connect() ,
listen() ,
socket() , the Base
Definitions volume of IEEE Std 1003.1-2001,
<sys/socket.h>
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base Specifications Issue
6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. In the event of any discrepancy between
this version and the original IEEE and The Open Group Standard, the original
IEEE and The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.opengroup.org/unix/online.html
.
